Mamertus
Life and witness
At Vienna, of St. Mamertus, bishop, who to pacify the wrath of God, first instituted in that city the solemn Litanies, three days before the Ascension of our Lord which; custom the universal Church afterwards received and approved.
Biographical overview
Mamertus (died c. 475) was the bishop of Vienne in Gaul, venerated as a saint. His primary contribution to ecclesiastical practice was the introduction of litanies prior to Ascension Day as an intercession against earthquakes and other disasters, leading to "Rogation Days." His feast day is the first of the Ice Saints.
Martyrologium Romanum · Latin witness
Viennae, in Gallia, sancti Mamerti Episcopi, qui, ob imminentem cladem, solemnes ante Ascensionem Domini triduanas in ea urbe Litanias instituit; quem ritum postea universalis Ecclesia recipiens comprobavit.